I've never heard it but have read various articles about it stating that it is completely normal and only occurs when the CPU is being placed under a lot of stress working overtime. So to answer the question, no it's not annoying at all because I've never heard it.

Apparently there is a 'Hissing sound' but i think people are just trying to find things wrong with the iPhone so they add a new 'Gate'. To me the iPhone was absolutely fine this time around. (in my opinion)

Mine has a pretty bad hiss when taking videos. I tested it in my quiet bedroom by taking a video of my room with the 7+ and then taking a video with my iPad. I also did a voice memo recording to see if that created a buzz and it wasn't present there.

Mine has a pretty bad hiss when taking videos. I tested it in my quiet bedroom by taking a video of my room with the 7+ and then taking a video with my iPad. I also did a voice memo recording to see if that created a buzz and it wasn't present there.

I know this thread is a little older, but I just returned an unlocked 7 Plus because it made a pretty bad hissing noise in videos, even when it wasn't completely quiet. Does every iPhone 7 do this? I've now been through 3 of them (2 AT&T and 1 Unlocked). This is honestly the only phone on the market that I want, but the video recording is terrible. We have one month old twins and I don't really want to ruin the first videos of them because of some hissing/popping noise in the background.

FWIW, I never noticed the processor hissing during just regular use - but it was absolutely present on videos.